// convert to light year.
#include <iostream>
using namespace std;

double to_distance(double lightyear);
int main(void)
{
    double lightyear, distance;

    cout << "Enter the number fo light years: ";
    cin >> lightyear;
    distance = to_distance(lightyear);

    cout << lightyear << " light years = " << distance
         << " astronomical units." << endl;
}

double to_distance(double lightyear)
{
    return lightyear * 63240;
}
